Muffler

ABSTRACT

A muffler ( 1 ) for an exhaust system ( 2 ) of an internal combustion engine, especially of a motor vehicle, with a muffler housing ( 3 ), which encloses a housing interior space ( 5 ), and with at least one exhaust gas-carrying hollow body ( 4 ) with two half shells in a half shell construction. The hollow body is arranged in the housing interior space ( 5 ). The two half shells ( 14, 15 ) of the hollow body ( 4 ) are fastened to one another in the area of a separating plane ( 16 ). The assembly of the muffler ( 1 ) or of the hollow body ( 4 ) can be simplified if the two half shells ( 14, 15 ) are fastened to one another by fastening elements ( 17, 18 ), which are formed directly on the half shells ( 14, 15 ).

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. §119 ofGerman Patent Application DE 10 2010 062 049.1 filed Nov. 26, 2010, theentire contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention pertains to a muffler for an exhaust system of aninternal combustion engine, especially of a motor vehicle.

BACKGROUND OF THE INVENTION

A muffler (also known as a silencer) usually comprises a mufflerhousing, which encloses a housing interior space, wherein at least oneexhaust gas-carrying hollow body is arranged in the housing interiorspace, for example, in the form of a tube, especially in the form of adeflecting tube or in the form of an X tube or Y tube.

Various possibilities are available for manufacturing such hollowbodies. They may be, for example, deep-drawn or manufactured in windingconstruction. A half shell construction is possible as well, in whichtwo half shells of the hollow body are attached to one another in thearea of a separating plane.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a muffler in animproved embodiment, which is characterized especially by an especiallyinexpensive manufacturability.

According to the invention, a muffler is provided for an exhaust systemof an internal combustion engine, especially of a motor vehicle. Themuffler comprises a muffler housing, which encloses a housing interiorspace. At least one exhaust gas-carrying hollow body in a half shellconstruction is arranged in the housing interior space. The two halfshells of the hollow body are fastened to one another in an area of aseparating plane, wherein the two half shells are fastened to oneanother by fastening elements which are formed directly on the halfshells.

The present invention is based on the general idea of fixing the twohalf shells directly mechanically to one another in a hollow body of ahalf shell construction, without additional fastening means having to beused for this. The present invention proposes for this to form fasteningareas or fastening elements, which cooperate with one another for themechanical connection of the two half shells, directly, i.e., integrallyon the half shells. These fastening areas or fastening elements maycooperate in the manner of a plug-type connection or clip connection orlocking connection or by a combination of the above connectiontechniques in order to fix the two half shells to one another. Thisleads to an especially simple handling for the assembly of the hollowbody, because all the needed fastening elements are formed directly onthe half shells, as a result of which additional, separate fasteningelements may be eliminated. In particular, a complicated screwconnection or a complicated welded connection can be eliminated. It isclear that the possibility of using additional, separate fasteningelements, for example, clamps or screws or weld points or weld seams tocomplement the assembly of the hollow body in addition to the fasteningelements formed integrally on the half shells shall not, in principle,be ruled out. However, the special advantage of the present inventionbeing presented here is seen in the fact that the fixing of the two halfshells to one another can be brought about exclusively by the fasteningelements already present directly on the half shells.

Especially advantageous is an embodiment in which the two half shellshave an outwardly projecting collar each in the area of the separatingplane on sides that are spaced apart from each other, wherein thefastening elements are formed on said collar and wherein the two halfshells are in contact with one another at these collars and are fastenedto one another. The collars define the relative position between the twohalf shells and are especially suitable for arranging the fasteningelements, because they are located outside a hollow space enclosed bythe hollow body and correspondingly do not compromise the exhaust gasducting in the hollow body.

According to an advantageous variant, at least one of the collars of onehalf shell may have a bracket located at a spaced location from theseparating plane as a fastening element, which extends in parallel tothe separating plane in the longitudinal direction of the respectivecollar and extends over the corresponding collar of the other half shellin a collar section used as a complementary fastening element. Thebracket forms a positive-locking connection, which securely fixes thetwo half shells to each other, with the corresponding collar section.

Preferred is an embodiment in which the corresponding collar of theother half shell has at least one interruption, through which thebracket can be passed during the assembly of the hollow body at rightangles to the separating plane, i.e., at right angles to thelongitudinal direction of the respective collar. A kind ofplug-in/pushing coupling is achieved as a result, in which the two halfshells must be moved in a first relative position in relation to oneanother at right angles to the separating plane in order for therespective bracket to be able to pass through the correspondinginterruption. This first relative motion or plug-in motion now followsat right angles to the separating plane. As soon as the two half shellsare in contact with one another via their collars in the separatingplane, a second relative motion takes place in the longitudinaldirection of the respective collar, which motion is within theseparating plane, in order for the respective bracket to be able toreach behind the corresponding collar section. This second relativemotion or pushing motion brings the two half shells into anotherrelative position, which corresponds to the assembled final state.

According to another embodiment, the respective bracket may extend,relative to the longitudinal direction of the respective collar, over abeginning area or end area of the corresponding collar of the other halfshell. Depending on the dimension of the collar, no interruption of thecollar, through which the bracket can be passed, is thus necessary, buta collar that is shortened compared to the collar having the bracket canrather also make available sufficient free space at the beginning areaor at the end area, through which free space the respective bracket canbe moved past at the collar section to be reached over during theplug-in operation in order to then extend over it during the pushingoperation.

Corresponding to another embodiment, the corresponding collar of theother half shell may have in the collar section extended over by thebracket at least one projection at right angles to the separating planein the direction of the bracket. A clamping action, which increases thefriction between the bracket and the collar section that is reachedover, can be produced or intensified by means of this projection. Thefixing of the two half shells to one another can be improved hereby.

The projection may be formed integrally, for example, by a stampingoperation on the respective collar, which simplifies the manufacture ofthe projection or of the half shell.

It is especially advantageous in this case if the respective bracket hasa locking contour, which locks with the respective projection. Apositive-locking connection is achieved due to the locking between thebracket and the projection in the pushing direction as well, i.e., inthe longitudinal direction of the brackets, which is in the separatingplane, as a result of which the final mounted position between the twohalf shells is secured.

The respective bracket may be opened from the respective collar inanother advantageous embodiment. In other words, the respective bracketis formed by cutting free or stamping free and opening directly orintegrally by a section of the bracket, which simplifies the manufactureof the respective half shell.

Especially advantageous is an embodiment in which a plurality ofbrackets are arranged on the same collar at spaced locations from oneanother in the longitudinal direction of the collar. A plurality offastening points or fastening sites can be obtained hereby, which arelocated at spaced locations from one another in the longitudinaldirection of the collar along the collars, which are in contact with oneanother. This leads to an especially effective fixing of the two halfshells.

According to another advantageous embodiment, each collar of one halfshell may have at least one bracket. This causes each collar of theother half shell to have at least one collar section over which therespective bracket can extend. The assembly of the hollow body becomessimpler due to this mode of construction, because the risk of confusingthe half shells is reduced. One half shell has all the brackets, whilethe other half shell has no bracket. Both the manual and mechanicalassembly of the two half shells is simplified hereby.

Corresponding to another embodiment, each collar of one half shell mayhave at least two brackets, while the collars of the other half shellhave at least one interruption each. While the respective first bracketwill thus cooperate with the respective interruption, the respectivesecond bracket can cooperate with another interruption or with abeginning area or end area of the respective bracket.

Corresponding to another embodiment, the hollow body may have at leastone exhaust gas inlet and at least one exhaust gas outlet, which areeach divided by the separating plane, preferably in half. The exhaustgas inlet and exhaust gas outlet are preferably located in a plane eachthat extends at right angles to the separating plane. An edge section ispreferably formed on the respective half shell for the exhaust gas inletand for the exhaust gas outlet, respectively, which edge section extendsover 180° of the exhaust gas inlet and of the exhaust gas outlet in thecircumferential direction.

The hollow body may be preferably a straight tube or a bent deflectingtube or a Y tube. While simple tubes have exactly one inlet and exactlyone outlet, a Y tube has either two inlets and one outlet or one inletand two outlets. An X-tube may, in principle, also form such a hollowbody.

At least one of the half shells may be provided with a perforation,through which the respective hollow body within the muffler can bepassed, for example, through an absorption chamber or through aresonance chamber or through an expansion chamber in order to produce acertain muffling effect.

It is apparent that the above-mentioned features, which will also beexplained below, are applicable not only in the particular combinationindicated but in other combinations or alone as well, without goingbeyond the scope of the present invention.

Preferred exemplary embodiments of the present invention are shown inthe drawings and will be explained in more detail in the followingdescription, where identical reference numbers designate identical orsimilar or functionally equivalent components. The various features ofnovelty which characterize the invention are pointed out withparticularity in the claims annexed to and forming a part of thisdisclosure. For a better understanding of the invention, its operatingadvantages and specific objects attained by its uses, reference is madeto the accompanying drawings and descriptive matter in which preferredembodiments of the invention are illustrated.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a highly simplified general view of a muffler with a hollowbody according to the invention;

FIG. 2 is a simplified top view of a hollow body designed as a Y tube;

FIG. 3 is a top view of a first half shell of the hollow body;

FIG. 4 is a top view of a second half shell of the hollow body;

FIG. 5 is a top view of the first half shell in the area of a bracket;

FIG. 6 a is a side view of the hollow body during assembly, in one ofdifferent states of assembly;

FIG. 6 b is a side view of the hollow body during assembly, in anotherof different states of assembly;

FIG. 6 c is a side view of the hollow body during assembly, in anotherof different states of assembly;

FIG. 7 is a side view of the hollow body in the area of a bracket foranother embodiment; and

FIG. 8 is a side view of the hollow body in the area of a bracket foranother embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings in particular, corresponding to FIG. 1, amuffler 1 of an exhaust system 2, which is shown in the area of themuffler 1 only and is used to remove exhaust gases of an internalcombustion engine, not being shown here, is arranged, together with theexhaust system 2, in a motor vehicle and has a muffler housing 3 and atleast one hollow body 4. The muffler housing 3 encloses a housinginterior space 5, which may be divided, for example, into a plurality ofchambers 6, 7, 8. Hollow body 4 is arranged in the housing interiorspace 5 and is used to guide the exhaust gas. As an example, and withoutlimitation of the general nature, an inlet tube 9 may be connected tothe muffler housing 3, where exhaust gas enters through the firstchamber 6 of the housing interior space 5. The first chamber acts as aninlet chamber or deflecting chamber, corresponding to arrows 10. Theexhaust gas enters, through the hollow body 4, the third chamber 8 ofthe housing interior space 5, which third chamber acts as a dischargechamber or deflection chamber, from which the exhaust gas is removed viaan outlet tube 11. Hollow body 4 is led, for example, through the secondchamber 7 of the housing interior space 5, which chamber acts as anabsorption chamber and is separated from the other two chambers 6, 8 bypartitions 12. Hollow body 4 may be made permeable to airborne sound inthe area of the second chamber 7, for example, by means of perforations13.

Hollow body 4 is manufactured as a half shell construction, so that ithas two half shells 14, 15, which are in contact with one another andfastened to one another in the area of a separating plane 16.

Corresponding to FIGS. 2 through 4, hollow body 4 may be, for example, aY tube. As an alternative, it may also be an X tube. As an alternative,the hollow body 4 may also be a bent deflecting tube or an unbent orstraight tube.

In addition, the perforations 13 provided in reference to FIG. 1 can berecognized in FIGS. 3 and 4.

Corresponding to FIGS. 2 through 8, the half shells 14, 15 are fastenedto one another by means of fastening elements 17, 18, these fasteningelements 17, 18 being formed directly at the half shells 14, 15. Inparticular, the fastening elements 17, 18 are formed integrally on therespective half shell 14, 15. The two half shells 14, 15 are preferablyfastened to one another exclusively via these fastening elements 17, 18formed directly on them. The half shells 14, 15 are, for example, shapedsheet metal parts, which are manufactured from one piece of sheet metalwith the respective fastening elements 17, 18.

To prepare these integrated fastening elements 17, 18, each half shell14, 15 has, in the area of the separating plane 16 on mutually distantsides 19, 20, an outwardly projecting collar 21 and 22 each, namely, afirst collar 21 at the one or first half shell 14 and a second collar 22at the other or second half shell 15. The fastening elements 17, 18 areformed at these collars 21, 22. These sides 19, 20 are preferably spacedapart from each other at right angles to a direction of flow 23 in thehollow body 4, which direction is indicated by an arrow. Hollow body 4thus has at least one exhaust gas inlet 24 and at least one exhaust gasoutlet 25. In the example shown of the hollow body 4 designed as a Ytube, a single inlet opening 24 and exactly two outlet openings 25 areobtained based on the direction of flow 23 assumed here. An oppositedirection of flow is, in principle, conceivable as well. Furthermore,both the inlet opening 24 and the two outlet openings 25 are arranged inthe example in planes that extend at right angles to the separatingplane 16. The separating plane 16 preferably divides the respectiveexhaust gas inlet 24 and the respective exhaust gas outlet 25 in half.

The two half shells 14, 15 are in contact with each other at theaforementioned collars 21, 22, which can be seen especially in FIG. 6through 8. Furthermore, the half shells 14, 15 are fastened to oneanother via these collars 21, 22, so that the collars 21, 22 arefastened to one another.

Preferred embodiments for the fastening elements 17, 18 will beexplained in more detail based on FIGS. 3 through 8. It is clear that itis also possible, in principle, to use other fastening elements 17, 18,which make possible the mechanical fixing of the two half shells 14, 15to one another and make do without additional, further fastening means,for example, clamps, screws or welded connections.

Corresponding to FIGS. 3 through 8, the two collars 21 of the first halfshell 14 have at least one bracket 26 each. In the preferred examplebeing shown, the respective collar 21 has two such brackets 26, so thatthe first half shell 14 has four brackets 26 in the example. Therespective bracket 26 represents the respective fastening element 17 ofthe first half shell 14. The respective bracket 26 extends in parallelto the separating plane 16 and at a spaced location therefrom in thelongitudinal direction of the respective collar 21, which said directionis indicated by arrows 27.

According to FIG. 4, the second half shell 15 has, at its two collars22, a collar section 28 for each bracket 26 of the first half shell 14,wherein said collar section represents a second fastening element 18complementary to bracket 26 or to the first fastening element 17. In theassembled state, which can be seen in FIGS. 6 c, 7 and 8, the respectivebracket 26 extends over the corresponding collar section 28.

In order for the respective bracket 26 to be able to extend over thecorresponding collar section 28, the respective collar 22 of the secondhalf shell 15 has, e.g., at least one interruption 29, which interruptsthe respective collar 22 in the longitudinal direction 27 thereof andwhich is dimensioned such that the respective bracket 26 can be passedthrough the respective interruption 29 at right angles to the separatingplane 16 and hence at right angles to the longitudinal direction 27 ofthe respective collar 21 or 22. The collars 22 of the embodiment shownin FIG. 4 show only one such interruption 29 each, which is adjoined byone of the collar sections 28 each. The other two collar sections 28 areformed, by contrast, at a beginning area 30 of the respective collar 22or, depending on the orientation of the longitudinal direction 27, at anend area of the respective collar 22. The corresponding bracket 26 canthus likewise be moved past the corresponding collar section 28 at rightangles to the separating plane 16.

FIGS. 2 through 4 thus show embodiments in which a plurality of brackets26 are arranged at the same collar 21 at spaced locations from oneanother in the longitudinal direction 27 of collar 21. Exactly twobrackets 26 per collar 21 are located at spaced locations from oneanother in the longitudinal direction 27 of the collar in the example.Furthermore, according to FIGS. 3 and 4, the brackets 26 are formedexclusively on the first half shell 16, while the collar sections 28associated with the brackets 26 are formed here exclusively on thesecond half shell 15.

The interruptions 29 can be prepared simply by punching out or cuttingout corresponding sections of the respective collar 22. The brackets 26can be prepared, by contrast, for example, by cutting free or punchingfree longitudinal sections within the respective collar 21 andsubsequently opening them, so that the brackets 26 form integral partsof collar 21.

FIG. 5 shows the first half shell 14 in the area of such a bracket 26cut free.

Corresponding to FIG. 6 c, the respective bracket 26 may be located atsuch a spaced location from the separating plane 16 that thecorresponding collar section 28 is clamped or clamped in with aprestress oriented at right angles to the separating plane 16. Inconjunction with the static friction, a holding force, which secures thehalf shells 14, 15 mounted on one another in the assembled state, can beproduced in this manner in parallel to the separating plane 16.

To increase this securing holding force, provisions may be madeaccording to FIGS. 7 and 8 for providing the respective collar section28 with at least one projection 31, which projects in the direction ofbracket 26 at right angles to the separating plane 16. When projection31 passes over the collar section 28, bracket 26 is thus displaced in adirection directed away from the separating plane 16, which increasesthe prestress with which bracket 26 is supported at the collar section28 or at the projection 31 thereof at right angles to the separatingplane 16. Such a projection 31 may be formed integrally, for example, bymeans of a stamping operation on the respective collar section 28.

According to FIG. 8, the respective bracket 26 may be provided,corresponding to an especially advantageous embodiment, with a lockingcontour 32, which is shaped such that it can lock with the respectiveprojection 31 as soon as the two half shells 14, 15 reach their mountedpositions. For example, the locking contour 32 projects from thecorresponding bracket 26 in the direction of the separating plane 16, asa result of which the locking contour 32 can extend behind therespective projection 31. A positive-locking connection is formed herebyin a direction in parallel to the separating plane 16.

In addition or as an alternative to the respective projection 31 and/orto the respective locking contour 32, at least one lead-in bevel 35 maybe provided, which is formed in the examples according to FIGS. 7 and 8at the free end of the bracket 26 in order to simplify the attachment ofthe respective bracket 26 to the corresponding collar section 28.

The assembly operation, by which the two half shells 14, 15 are fastenedto one another in order to form the hollow body 4, will be explained inmore detail below on the basis of FIGS. 6 a through 6 c.

Corresponding to FIG. 6 a, the two half shells 14, 15 are at firstpositioned in relation to one another to set a starting position suchthat the respective bracket 26 is directed at right angles to theseparating plane 16 aligned with the corresponding interruption 29. Thetwo half shells 14, 15 are then moved towards one another correspondingto arrows 33 at right angles to the separating plane 16. The respectivebracket 26 can now pass through the corresponding interruption 29, as aresult of which the intermediate position shown in FIG. 6 b is reached.The collars 21, 22 are in contact with one another in the separatingplane 16 in this intermediate position. This first adjusting motionaccording to arrows 33 represents a plug-in operation. This plug-inoperation is now followed by a pushing operation, during which the twohalf shells 14, are moved against each other in parallel to theseparating plane 16 corresponding to arrows 34, so that the respectivebracket 26 can extend over the corresponding collar section 28. At theend of this pushing motion according to the arrows 34, the relativeposition according to FIG. 6 c is present, which represents an endposition or a completely assembled state.

While specific embodiments of the invention have been shown anddescribed in detail to illustrate the application of the principles ofthe invention, it will be understood that the invention may be embodiedotherwise without departing from such principles.

1. A muffler for an exhaust system of an internal combustion engine, themuffler comprising: a muffler housing, which encloses a housing interiorspace; and at least one exhaust gas-carrying hollow body comprising twohalf shells providing a half shell construction, said hollow body beingarranged in said housing interior space, wherein: said two half shellsof said hollow body are fastened to one another in an area of aseparating plane; and said two half shells are fastened to one anotherby fastening elements, which are formed directly on the half shells. 2.A muffler in accordance with claim 1, wherein: in an area of theseparating plane on sides spaced apart from each other, said two halfshells each have an outwardly projecting collar, on which the fasteningelements are formed; and said two half shells are in contact with oneanother and are fastened to one another at the respective said collar.3. A muffler in accordance with claim 2, wherein: at least one saidcollar has a bracket located at a spaced location from the separatingplane, the bracket forming a fastening element, which extends inparallel to the separating plane in a longitudinal direction of therespective said at least one said collar and extends over thecorresponding said collar of the other said half shell in a collarsection acting as a complementary fastening element.
 4. A muffler inaccordance with claim 3, wherein the corresponding collar of the otherhalf shell has at least one interruption, through which said bracket canbe passed, during assembly of the hollow body, at right angles to thelongitudinal direction of said collar.
 5. A muffler in accordance withclaim 3, wherein in regard to the longitudinal direction of therespective collar, the respective bracket reaches over a beginning areaor an end area of the corresponding collar of the other half shell.
 6. Amuffler in accordance with claim 3, wherein the corresponding collar ofthe other half shell has a projection, projecting in a direction of thebracket, at right angles to the separating plane in a collar sectionover which said bracket extends.
 7. A muffler in accordance with claim6, wherein said projection is formed by a stamping operation on therespective collar.
 8. A muffler in accordance with claim 6 or 7, whereinthe respective bracket has a locking contour, which is locked with therespective projection.
 9. A muffler in accordance with claim 3, whereinthe respective bracket is opened from the respective collar.
 10. Amuffler in accordance with claim 3, wherein a plurality of brackets arearranged on the same collar at spaced locations from one another in thelongitudinal direction of the collar.
 11. A muffler in accordance withclaim 3, wherein each collar of one half shell has at least one bracket.12. A muffler in accordance with claim 3, wherein said collar of said atleast one half shell has another bracket to provide at least twobrackets, whereas said collar of the other said half shell has at leastone interruption.
 13. A muffler internal in accordance with claim 1,wherein the hollow body has at least one exhaust gas inlet and at leastone exhaust gas outlet and a separating plane, a region of said exhaustgas inlet being divided from a region of said exhaust gas outlet by saidseparating plane.
 14. A muffler in accordance with claim 1, wherein saidhollow body is one of a straight tube, a bent deflecting tube, a Y tubeand an X tube.
 15. A muffler for an exhaust system of an internalcombustion engine, the muffler comprising: a muffler housing defining ahousing interior space; and an exhaust gas-carrying hollow body arrangedin said housing interior space, said hollow body comprising a first halfshell with a first half shell fastening element formed directly on saidfirst half shell and a second half shell with a second half shellfastening element formed directly on said second half shell, said firsthalf shell and said second half shell being fastened together by saidfirst half shell fastening element and said second half shell fasteningelement in an area of a separating plane to provide a half shellconstruction.
 16. A muffler in accordance with claim 15, wherein: saidfirst half shell has an outwardly projecting collar on which said firsthalf shell fastening element is formed in the area of the separatingplane on one side; said first half shell has another outwardlyprojecting collar on which another first half shell fastening element isformed in the area of the separating plane on another side; said secondhalf shell has an outwardly projecting collar on which said second halfshell fastening element is formed in the area of the separating plane onsaid one side; said second half shell has another outwardly projectingcollar on which another second half shell fastening element is formed inthe area of the separating plane on said another side; said one side isspaced apart from said another side; said first half shell and saidsecond half shell are in contact with one another and are fastened toone another at the respective said collars.
 17. A muffler in accordancewith claim 16, wherein: said first half shell fastening elementcomprises a bracket of said outwardly projecting collar of said firsthalf shell; and said second half shell has a collar section acting as acomplementary fastening element to said bracket.
 18. A muffler inaccordance with claim 17, wherein said collar of said second half shellhas an interruption, through which said bracket is passed at rightangles to a longitudinal direction of said collar of said second halfshell during assembly of said hollow body,
 19. A muffler in accordancewith claim 17, wherein collar section has a projection, projecting in adirection of said bracket, at right angles to the separating plane andover which said bracket extends.
 20. A muffler in accordance with claim19, wherein: said projection is formed by a stamping operation on therespective collar; and said bracket has a locking contour, which islocked with said projection.